package com.lleice.common.utils;
import java.io.UnsupportedEncodingException;
 

/**
 * 取得给定汉字串的首字母串,即声母串
 * Title: ChineseCharToEn
 * @date 2004-02-19 注：只支持GB2312字符集中的汉字
 * @author lleice
 *
 */
public final class ChineseCharToEn {
	private final static int[] LI_SEC_POS_VALUE = { 1601, 1637, 1833, 2078, 2274,
			2302, 2433, 2594, 2787, 3106, 3212, 3472, 3635, 3722, 3730, 3858,
			4027, 4086, 4390, 4558, 4684, 4925, 5249, 5590 };
	private final static String[] LC_FIRST_LETTER = { "a", "b", "c", "d", "e",
			"f", "g", "h", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s",
			"t", "w", "x", "y", "z" };
	private final static int POS_CODE = 1600;
	private final static int SEC_POS_CODE = 5590;
	private final static int LOPE_COUNT = 23;
 
	/**
	 * 取得给定汉字串的首字母串,即声母串
	 * @param str 给定汉字串
	 * @return 声母串
	 */
	public static String getAllFirstLetter(String str) {
		if (str == null || str.trim().length() == 0) {
			return "";
		}
 
		String strs = "";
		for (int i = 0; i < str.length(); i++) {
			strs = strs + getFirstLetter(str.substring(i, i + 1));
		}
 
		return strs;
	}

	/**
	 * 取得给定汉字的首字母,即声母
	 * @param chinese 给定的汉字
	 * @return 给定汉字的声母
	 */
	public static String getFirstLetter(String chinese) {
		if (chinese == null || chinese.trim().length() == 0) {
			return "";
		}
		chinese = conversionStr(chinese, "GB2312", "ISO8859-1");
		// 判断是不是汉字
		if (chinese.length() > 1) 
		{
			// 汉字区码
			int liSectorCode = (int) chinese.charAt(0); 
			// 汉字位码
			int liPositionCode = (int) chinese.charAt(1); 
			liSectorCode = liSectorCode - 160;
			liPositionCode = liPositionCode - 160;
			// 汉字区位码
			int liSecPosCode = liSectorCode * 100 + liPositionCode; 
			if (liSecPosCode > POS_CODE && liSecPosCode < SEC_POS_CODE) {
				for (int i = 0; i < LOPE_COUNT; i++) {
					if (liSecPosCode >= LI_SEC_POS_VALUE[i]
							&& liSecPosCode < LI_SEC_POS_VALUE[i + 1]) {
						chinese = LC_FIRST_LETTER[i];
						break;
					}
				}
			} else 
			{
				// 非汉字字符,如图形符号或ASCII码
				chinese = conversionStr(chinese, "ISO8859-1", "GB2312");
				chinese = chinese.substring(0, 1);
			}
		}
 
		return chinese;
	}
 
	/**
	 * 字符串编码转换
	 * @param str 要转换编码的字符串
	 * @param charsetName 原来的编码
	 * @param toCharsetName 转换后的编码
	 * @return 经过编码转换后的字符串
	 */
	private static String conversionStr(String str, String charsetName,String toCharsetName) {
		try {
			str = new String(str.getBytes(charsetName), toCharsetName);
		} catch (UnsupportedEncodingException ex) {
			System.out.println("字符串编码转换异常：" + ex.getMessage());
		}
		return str;
	}
 
}
